The present invention generally relates to electronic devices and more particularly to multi-stacked electronic devices having improved solderability.
A multi-stacked electronic device may be formed by two or more electronic components disposed one on top of another. Each electronic component may include leadframes extending from the package. The leadframes are external electrical connections that may allow to join the multi-stacked electronic device to printed circuit boards (PCBs) or other electronic devices. A soldering process may be typically conducted to attach the multi-stacked electronic device via the leadframes to the PCB. Prior to soldering the multi-stacked electronic device to the PCB, a metal joining process may be conducted to physically and electrically connect the leadframes of each electronic component.
The soldering process may generally include melting and flowing a filler or solder metal into a solder joint. Good solderability may be related to wetting by the solder material. When good wetting conditions are achieved, a uniform and adherent coat of solder may fill the solder joint efficiently bonding the multi-stacked electronic device to the PCB. In contrast, if wetting conditions are not satisfactory, poor solderability may be observed causing problems such as dewetting of the solder joint. Dewetting may occur when the solder metal coating a surface withdraws from the solder joint creating irregularly shaped heaps of solder metal separated by areas covered with a thin film of solder metal. Dewetted areas may negatively affect adhesion of the multi-stacked electronic device to the PCB.